From: Dan Clemmensen (dgc@shirenet.com)
Date: Sat Aug 10 1996 - 08:35:53 MDT
Alexander 'Sasha' Chislenko wrote:
>
> If the construction of those organisms (DNA?) is to any degree compatible with
> those on Earth, it would be a very strong evidence for panspermia to have worked
> at least in this case. Then it probably would be that hard to guess whether
> these
> life forms came from Mars, from Earth, or to both from elsewhere.
>
There have been several articles in Science magazine about the martian
meteorites. Smoe of teh articles have discussed the energetics and
balistics
of the transfer of the material from Mars' surface to earth. Basically,
a large
bolide struck Mars, "splashing" the material laterally off the surface,
through
the thin martian atmosphere, an out into space in excess of martian
escape
velocity. (Assuming that I understood the articles correctly and that I
remember
them correctly.) Thus, transfer of material from Mars to Eath is
feasible.
I don't recall a discussion of whetern or not such a transfer is
compatible
with the preservation of bacterial life, but it's not inconcievable. I
don't
think acceleration or even shock is a mojor issue for rock-dwelling
bacteria.
the problems would be heat (at launch and re-entry) and dessication and
radiation (in space).
The situation for Earth-to-Mars transfer is a lot less favorable, for
three
reasons: Earth has higher gravity, Earth has (and apparently has had) a
much
denser atmosphere, and Earth is nearer to the sun. For all three
reasons, it's
a lot harder to get a rock from earth to Mars without starting with
enough energy to melt it.
Panspermia requires a much longer time in space than Mars-to-Earth
infection. Thus, Mars-to-earth infection is much more probable than
either Earth-to-Mars infection or infection from a common source, IMO.
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